Such a support identification device is generally known in the art. Therein, the identity transmitter terminals of the support are all set to a logical level 0 or 1 so that they together correspond to an identity that can be recognized by the identity receiver coupled thereto. An example of such a support identification device is a rack or a backplane, e.g. of a telecommunication system, with a connector comprising the identity transmitter terminals or pins to which a corresponding connector of a printed circuit board able to be inserted in the rack can be coupled as the identity receiver.
When the printed circuit board or card is inserted into the support or rack, the identity transmitter terminals or pins of the rack connector identify the type of rack; each pin is hardware-wired to the ground or to a voltage terminal, e.g. Vcc (logical level 0 or 1). As example, n=4 pins could be used to this end. The support identification is then limited to 2n=24=16 types of supports or racks.
A first solution to increase the number of possible identification types is to increase the number of identity transmitter terminals or pins. However, there will always be a physical limitation to the number of available pins.
Another solution is to place a serial interface, e.g. to connect the pins to a serial PROM in the support. However, the support or rack is not adapted to receive an active device or card.